Sigma Piscium
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pisces[1] |
| Right ascension | 01h 02m 49.09645s[2] |
| Declination | +31° 48′ 15.3471″[2] |
| Apparent magnitude (V) | +5.50[3] |
| Characteristics | |
| Spectral type | B9.5V + B9.5V[4] |
| U−B color index | −0.20[5] |
| B−V color index | −0.04[5] |
| Astrometry | |
| Radial velocity (Rv) | 10.4 ± 0.9[6] km/s |
| Proper motion (μ) | RA: 14.33[2] mas/yr Dec.: −30.25[2] mas/yr |
| Parallax (π) | 8.86±0.07 mas[2] |
| Distance | 368 ± 3 ly (112.9 ± 0.9 pc) |
| Absolute magnitude (MV) | −-0.12[1] |
| Orbit[4] | |
| Period (P) | 81.12625 ± 2.7 d |
| Semi-major axis (a) | 5.56 ± 0.04 mas |
| Eccentricity (e) | 0.8956 ± 0.0020 |
| Inclination (i) | 143.4 ± 1.3° |
| Longitude of the node (Ω) | 167.8 ± 1.7° |
| Periastron epoch (T) | MJD 31308.153 ± 0.023 |
| Argument of periastron (ω) (secondary) | 346.6 ± 2.0° |
| Semi-amplitude (K1) (primary) | 53.2 ± 1.9 km/s |
| Semi-amplitude (K2) (secondary) | 59.6 ± 1.6 km/s |
| Details[4] | |
| σ Psc A | |
| Mass | 2.65 ± 0.27 M☉ |
| σ Psc B | |
| Mass | 2.36 ± 0.24 M☉ |
| Other designations | |
| σ Psc, 69 Psc, BD+31°168, HD 6118, HIP 4889, HR 291, SAO 54374, PPM 65899 | |
| Database references | |
| SIMBAD | data |
Sigma Piscium (Sigma Psc, σ Piscium, σ Psc) is a binary star in the zodiac constellation of Pisces. It has an apparent magnitude of +5.50, meaning it is barely visible to the naked eye, according to the Bortle scale. While parallax measurements by the Hipparcos spacecraft give a distance of approximately 430 light years (133 parsecs),[2] dynamical parallax measurements put it slightly closer, at 368 light-years (113 parsecs) from Earth.[4]
Sigma Piscium is a spectroscopic binary system, meaning the components of the system have been detected from periodic Doppler shifts in their spectra. In this case, light from both stars can be detected and it is double-lined. It has an orbital period of 81 days, and the orbit is relatively eccentric, at about 0.9. Both components are B-type main-sequence stars.[4]
Sigma Piscium is moving through the Milky Way at a speed of 23.5 km/s relative to the Sun. Its projected galactic orbit carries it between 24,300 and 29,400 light years from the center of the galaxy.[7]
Sigma Piscium was a latter designation of 40 Andromedae.[8]
Naming
[edit | edit source]In Chinese, 奎宿 (Kuí Sù), meaning Legs, refers to an asterism consisting of σ Piscium, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, β Andromedae, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ1 Piscium. Consequently, the Chinese name for σ Piscium itself is 奎宿十 (Kuí Sù shí, English: the Tenth Star of Legs.)[9] Sigma Piscium, however, is also identified with Kuísùzēngshíwǔ (奎宿增十五), the 15th additional star in the Legs asterism.[10]
References
[edit | edit source]- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). XHIP record for this object at VizieR.
- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日 Archived 2016-03-03 at the Wayback Machine
- ^ zh:奎宿增十五
